Well, this is one of those things that we could spend a lot of time on, but here are a few tips.- Your Extensibility project will reference your UI assemblies, etc. but your UI assemblies WILL NOT reference the extensibility.
- When assigning a type editor to a property within a class in your UI assembly, you will want to use a constant defined somewhere within your UI assembly that has the full name to the assembly and class that you want to use. This prevents the need to the reference within the UI assembly to the Extensibility assembly.
Basically if you follow these two rules (which were the hardest to get through our heads initially) you will be in good shape.